Method for forming precoat film and method for forming silicon-containing film

ABSTRACT

A method for forming a precoat film on a metal surface in a chamber before forming a silicon-containing film having an identical composition system with that of the precoat film on a substrate in the chamber using a PECVD method, wherein the precoat film is formed using a PEALD method in which a first gas and a second gas are supplied into the chamber by shifting timing of supply, the PEALD method comprises an adsorption step comprising supplying the first gas into the chamber so that the source gas component adsorbs on the metal surface, a first purge step comprising discharging an excessive source gas component not adsorbed on the metal surface, and a precoat film forming step comprising supplying the second gas into the chamber and applying high-frequency power to generate plasma in the reactant gas component in the second gas.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of and priority to U.S. Provisional Application No. 63/010,357, filed on Apr. 15, 2020 in the United States Patent and Trademark Office, the disclosure of which is incorporated herein in its entirety by reference.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a method for forming a precoat film on a metal surface in a chamber used in a plasma-enhanced chemical vapor deposition (PECVD) method, and a method of producing a silicon-containing film using the chamber in which the precoat film is formed.

Related Art

In the plasma-enhanced chemical vapor deposition (PECVD) method, a source gas and a reactant gas are supplied into a reaction vessel (chamber) in which a substrate is disposed, and plasma is generated to form a film on a surface of the substrate. This method is used for forming a film such as an insulating film on a substrate, such as a semiconductor wafer, in a semiconductor manufacturing process. However, when a film is formed (film formation) on a surface of a substrate using the PECVD method, the reaction taking place in the chamber is sometimes destabilized, or the substrate is contaminated with a metal part in some cases. As a measure for stabilizing the reaction taking place in the chamber and reducing contamination of a substrate with a metal part, for example, it is useful to form a precoat film on a metal surface in the chamber, including an inner wall surface of the chamber and a surface of a metal part, such as an electrode, disposed in the chamber, prior to film formation by a PECVD method.

As a conventional method of forming such a precoat film, for example, Patent Document 1 discloses a film forming method including, before a step of disposing a substrate to be treated in a reaction vessel (chamber), introducing a gas for forming the precoat film while plasma is being generated in the chamber to form the precoat film in the chamber, so that when the substrate is disposed in the chamber, the precoat film to be formed on the substrate is a compressive film and its stress is lower than that of an insulating film (formed by a PECVD method).

-   Patent Document 1: Japanese Patent No. 3725100

SUMMARY OF THE INVENTION

In a film forming device used in the PECVD method, a metal or an alloy containing one of aluminum (Al) and copper (Cu) or both are generally used for an inner wall surface of a chamber or a part disposed in the chamber. When a silicon-containing film is formed on a surface of a substrate by the PECVD method, a chlorosilane compound is generally used as a source gas. However, when a precoat film is formed on a metal surface in a chamber, such as an inner wall surface of the chamber and a surface of a metal part disposed in the chamber, such as an electrode, by the PECVD method prior to forming a silicon-containing film on a surface of a substrate by the PECVD method, chlorine is released from the chlorosilane compound as the source gas component due to plasma, the free chlorine etches the metal surface in the chamber, and a metal component released from the metal surface by etching tends to remain in the chamber as released. If a silicon-containing film is formed on a surface of a substrate by the PECVD method in a state in which a metal component remains in the chamber, likelihood that the surface of the substrate is contaminated with metal increases. If a silicon-containing film is formed on the surface of the substrate contaminated with metal, a silicon-containing film with a good quality is less likely to be obtained. Therefore, it is desired to reduce metal contamination on a substrate surface when forming a silicon-containing film.

An aspect of the method for forming a precoat film of the present disclosure is used in the PECVD method and the PECVD method comprises supplying at least a first gas containing a chlorosilane compound as a source gas and a second gas containing a reactant gas into a metal chamber in which a substrate is disposed, and applying high-frequency power in an atmosphere in which the source gas component and the reactant gas component exist, to generate plasma to form a silicon-containing film on the surface of the substrate. In an aspect of the method for forming a precoat film of the present disclosure, the precoat film is formed on a metal surface in a chamber including an inner wall surface of the chamber and a surface of a metal part disposed in the chamber, before forming a silicon-containing film having the same composition system as the precoat film. The precoat film is formed using a PEALD method, in which a first gas and a second gas are supplied into the chamber by shifting the timing of supply. An aspect of the method for forming a precoat film of the present disclosure includes an adsorption step comprising supplying the first gas into a chamber, so that the source gas component adsorbs on the metal surface in the chamber, a first purge step comprising discharging an excessive source gas component not adsorbed on the metal surface in the chamber, out of the chamber, and a precoat film forming step comprising supplying the second gas into the chamber and applying high-frequency power in an atmosphere in which the second gas exists in the chamber, to generate plasma in the reactant gas component in the second gas, so that the reactant gas component reacts with the source gas component adsorbed on the metal surface in the chamber to form the precoat film on the metal surface.

Further, an aspect of the method for producing a silicon-containing film of the present disclosure is configured to comprise forming a precoat film on a metal surface in a chamber using a PEALD method, and then forming a silicon-containing film on a surface of a substrate, using a PECVD method. Among them, the method for forming a precoat film using a PEALD method is configured to comprise: an adsorption step comprising supplying a first gas containing a chlorosilane compound as a source gas component into a metal chamber, so that the source gas component adsorbs on a metal surface in the chamber including an inner wall surface of the chamber and a surface of a metal part disposed in the chamber; a first purge step comprising discharging an excessive source gas component which does not adsorb on the metal surface in the chamber, out of the chamber; and forming a precoat film by supplying a second gas containing a reactant gas into the chamber and applying high-frequency power in an atmosphere in which the second gas exists, thereby generating plasma in the reactant gas component in the second gas, so that the reactant gas component reacts with the source gas component adsorbed on the metal surface in the chamber to form the precoat film on the metal surface. The step of forming a silicon-containing film using a PECVD method is configured to comprise disposing a substrate in the chamber and supplying at least the source gas component and the reactant gas component into the chamber, and applying high-frequency power in an atmosphere in which both the source gas component and the reactant gas exist, to generate plasma, so that the silicon-containing film is formed on the substrate.

According to the above embodiments of the present disclosure, for example, it is possible to provide a method for forming a precoat film and a method for producing a silicon-containing film, the methods being capable of suppressing a metal component contained in an inner wall surface of the chamber or a part disposed in the chamber from contaminating a substrate surface or a silicon-containing film formed on the substrate surface, even when the silicon-containing film is formed by the PECVD method.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a vertical cross-sectional view schematically showing a film forming device used in an embodiment of the present invention;

FIG. 2 is a schematic drawing showing supply paths for supplying a chlorosilane compound, a reactant gas and a carrier gas in the film forming device;

FIG. 3 is a graph showing an example of an increase and decrease in flow rates of a source gas (chlorosilane compound), a reactant gas and a carrier gas, and an example of on/off of high-frequency power applied to generate RF plasma, in the precoat film forming step of the Example of the present invention; and

FIG. 4 is a graph showing an example of an increase and decrease in flow rates of a source gas (chlorosilane compound), a reactant gas and a carrier gas, and an example of on/off of high-frequency power applied to generate RF plasma, in the silicon-containing film forming step of the Example of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, specific embodiments of the present invention are described in detail with reference to the drawings. Note that, the present invention is not limited to the following embodiments, but can be variously changed within a range not departing from the gist of the present invention.

<<Method for Forming Precoat Film>>

The method for forming a precoat film according to the present embodiment is performed before forming a silicon-containing film on a substrate in a metal chamber, and the precoat film has the same composition system as the silicon-containing film. The method for forming the silicon-containing film on a substrate in the chamber is performed using a PECVD method, and the PECVD method comprises at least supplying a first gas comprising a chlorosilane compound as a source gas component and a second gas comprising a reactant gas into the chamber comprising the substrate disposed, and applying high-frequency power in an atmosphere in which both the source gas and the reactant gas exist in the chamber, to generate plasma, so that the silicon-containing film is formed on the substrate. The precoat film is formed using a PEALD method, in which the first gas and the second gas are supplied into the chamber by shifting timing of supply. The method for forming a precoat film according to an embodiment of the present invention comprises an adsorption step comprising supplying the first gas into a chamber, so that the source gas component adsorbs on the metal surface in the chamber; a first purge step comprising discharging an excessive source gas component not adsorbed on the metal surface in the chamber, out of the chamber; and a precoat film forming step comprising supplying the second gas into the chamber and applying high-frequency power in an atmosphere in which the second gas exists in the chamber, to generate plasma in the reactant gas component in the second gas, so that the reactant gas component reacts with the source gas component adsorbed on the metal surface in the chamber to form the precoat film on the metal surface.

The method for forming a precoat film according to the present embodiment is performed using a PEALD method and comprises an adsorption step comprising making a source gas component containing a chlorosilane compound adsorb on a metal surface in a chamber; a first purge step comprising discharging an excess source gas component not adsorbed on the metal surface out of the chamber; and then generating plasma in the reactant gas component contained in the second gas, so that the reactant gas component reacts with the source gas component to form the precoat film on the metal surface. Thereby, plasma is not generated while the chlorosilane compound is being adsorbed on the metal surface in the chamber, and an excess source gas component not adsorbed on the metal surface is discharged by the first purge step and then plasma is generated. This configuration allows the amount of chlorine released by decomposition of the chlorosilane compound by plasma to be reduced, resulting in reduction in contamination of the chamber by metal atoms, such as aluminum (Al) and copper (Cu), when forming the precoat film. In addition, forming a precoat film by a plasma-enhanced atomic layer deposition (PEALD) process enables a metal surface in the chamber to be protected from being etched by chlorine generated by decomposition of the chlorosilane compound, when forming a silicon-containing film by a PECVD method. Therefore, using the precoat film thus formed achieves reduction in contamination of the surface of the substrate and the silicon-containing film formed on the surface of the substrate by metal atoms, when forming a silicon-containing film by a PECVD method.

The method for forming a precoat film according to the present embodiment allows a precoat film to be formed from the same raw materials as the materials used for forming a silicon-containing film by a PECVD method, and using a device similar to that used for forming a silicon-containing film by a PECVD method. Therefore, unlike a case of forming a yttria coat as the precoat film, it is possible to obtain a precoat film which can reduce contamination by metal atoms of a substrate surface or a silicon-containing film formed on the substrate surface without using an expensive and special raw material or a device.

<Film Forming Device>

The film forming device used in the method for forming a precoat film according to the present embodiment is not particularly limited, but the film forming device 1 as shown in FIG. 1, for example, can be used.

FIG. 1 is a vertical cross-sectional view schematically showing a film forming device used in an embodiment of the present invention. In the film forming device 1 of FIG. 1, a silicon-containing film is formed on a surface of a substrate W such as a wafer by a plasma-enhanced chemical vapor deposition (PECVD) method.

The film forming device 1 includes a chamber 10 having an upper opening, and a mounting table 12 which is provided in the chamber 10 and on which a substrate W is to be mounted.

The chamber 10 is electrically grounded by a grounding wire (not shown). The inner wall surface of the chamber 10 is made of a metal or an alloy containing, for example, one of aluminum (Al) and copper (Cu) or both in order to make it conductive with the ground wire. In addition, it is preferable that parts such as the mounting table 12, the supporting member 13 thereof, and the gas supply unit 14, which are disposed in the chamber 10, are also made of a metal or an alloy containing one of aluminum (Al) and copper (Cu) or both from the viewpoint of making them conductive to one of the electrodes for generating plasma.

However, when a metal surface in the chamber 10, more specifically, an inner wall surface of the chamber 10 or a surface of a metal part (the mounting table 12, the supporting member 13, the gas supply unit 14, or the like) disposed in the chamber 10 comprises a metal or an alloy containing one of aluminum (Al) and copper (Cu) or both, plasma decomposes the chlorosilane compound, which is a source gas component contained in the first gas, resulting in release of free chlorine, which etches the metal surface in the chamber 10, generating metal atoms, which contaminate a substrate W and a surface of the silicon-containing film formed on the substrate W. In this respect, according to the method for forming the precoat film of the present embodiment, a step comprising discharging an excess source gas component not adsorbed on the metal surface out of the chamber enables etching of a metal surface in the chamber 10 to be minimized, when forming the precoat film 2. In addition, using the precoat film 2 formed by this method enables a metal surface in the chamber 10 to be protected from being etched by chlorine, when a silicon-containing film is formed by a PECVD method.

Among the metal parts disposed in the chamber 10, the mounting table 12 is configured such that a lower surface thereof is supported by a support member 13 formed of a conductive material and is electrically connected to the support member 13. In addition, a heater (not shown) is built in the mounting table 12, and the substrate W mounted on the mounting table 12 can be heated to a predetermined temperature.

The support member 13 supporting the mounting table 12 is electrically connected to a bottom surface of the chamber 10. Thereby, the mounting table 12 is grounded through the chamber 10, and thus functions as a lower electrode when generating plasma. The lower portion of the support member 13 extends downward through an insertion hole 11 formed in the center portion of the bottom portion of the chamber 10. The support member 13 is movable up and down by an elevating mechanism (not shown), whereby the mounting table 12 is configured to be elevatable.

On the other hand, above the mounting table 12, the gas supply unit 14 is provided in parallel to face the mounting table 12. That is, the gas supply unit 14 is disposed so as to face the substrate W mounted on the mounting table 12.

The gas supply unit 14 supplies a processing gas for processing the substrate W to the substrate W. A supply source (not shown) for the gas (processing gas) to be used for forming a precoat film or a silicon-containing film is connected to the gas supply unit 14 via a gas supply pipe outside the film forming device 1. The processing gas supplied to the gas supply unit 14 is introduced into the chamber 10 through a gas supply hole 15 in a form of a shower. Further, the gas supply pipe outside the film forming device 1 has a piping structure, for example, as shown in FIG. 2, and is provided with a gas supply condition adjusting section including valves V1 to V11 and a mass flow controller (not shown), and can adjust gas supply conditions such as a gas type, a gas mixing ratio, and a flow rate of gas supplied as a processing gas.

This gas supply unit 14 functions as an upper electrode, when generating plasma. High-frequency power source that supplies high-frequency power and generates plasma (RF plasma) is electrically connected to the gas supply unit 14 through a matching device (not shown). The high-frequency power source, for example, is configured to be able to output high-frequency power having a frequency of 100 kHz to 100 MHz. The matching device matches internal impedance to load impedance of high-frequency power source, and when plasma is generated in the chamber 10, the matching device works so that the internal impedance and the load impedance of the high-frequency power source are apparently identical to each other.

Here, a size of a gap D between the mounting table 12 functioning as a lower electrode and the gas supply unit 14 functioning as an upper electrode may be within a range in which plasma can be generated between the mounting table 12 and the gas supply unit 14, and may be, for example, within a range of 7 mm or more and 15 mm or less.

The outer peripheral portion of the upper surface of the gas supply unit 14 is held by an annular supporting member 16. The support member 16 is made of an insulating material such as quartz, for example, and the gas supply unit 14 and the chamber 10 are electrically insulated.

In addition, a plurality of support pins (not shown) are provided in the chamber 10 so as to penetrate through insertion holes (not shown) formed in the mounting table 12 and support the substrate W at the upper end when the mounting table 12 is lowered. Here, the substrate W supported by the upper end portions of the support pins is transferred to and from a transfer arm (not shown) that enters and leaves the inside and outside of the chamber 10.

In addition, an exhaust mechanism (not shown) that exhausts the inside of the chamber 10 is connected to a side of the chamber 10. Atmosphere in the chamber 10 can be exhausted by driving the exhaust mechanism, and the pressure in the chamber 10 can be reduced to a predetermined vacuum degree.

<Precoat Film Formation>

In the method for forming a precoat film according to the present embodiment, a precoat film 2 having the same composition system as a silicon-containing film, described below, is formed by a PEALD method prior to formation of the silicon-containing film using a PECVD method. The precoat forming method by the PEALD comprises at least an adsorption step comprising making a source gas component adsorb on a metal surface in the chamber 10, a first purge step comprising discharging an excessive source gas component not adsorbed on the metal surface in the chamber 10 out of the chamber 10, and generating plasma in a reactant gas component, so that the reactant gas component reacts with the source gas component adsorbed on the metal surface.

The precoat film 2 formed in the present embodiment has the same composition system as the silicon-containing film formed by a PECVD method, and is a film containing at least silicon. Examples of the silicon-containing film formed by the PECVD method include an SiN film or an SiO₂ film. Examples of the precoat film 2 include an SiN film or an SiO₂ film, similarly to the silicon-containing film. In particular, in the present embodiment, when forming the precoat film 2 by a PEALD method, a chlorosilane compound as a source gas component is supplied into the chamber, an excessive chlorosilane compound other than the source gas component adsorbed on the metal surface in the chamber is purged, a reactant gas is supplied into the chamber, and then plasma is generated in the chamber. Therefore, an amount of free chlorine released by decomposition of the chlorosilane compound by plasma can be suppressed to a minimum, resulting in reduction in the amount of free chlorine. Thereby, since the metal surface in the chamber 10 can be prevented from being etched, metal contamination in the chamber 10 can be suppressed as compared with a case in which the precoat film 2 is formed by a PECVD method.

[Preparation of Chamber]

The precoat film 2 is formed in a state in which the substrate W is not disposed into the chamber 10. When an old precoat film is formed in the chamber 10, it is preferable to remove the old precoat film by using NF₃ or the like in advance.

The chamber 10 is heated using a heater. Here, the heating temperature of the chamber 10 can be, for example, in the range of 150 to 500° C., and is preferably maintained at a constant temperature until the precoat film 2 is formed.

At the same time, a carrier gas is supplied into the chamber 10, and the internal pressure is reduced. Here, as the carrier gas, for example, one or more selected from the group consisting of argon (Ar) gas, nitrogen (N₂) gas, and helium (He) gas can be used. The internal pressure of the chamber 10 may be pressure within a range applicable to a typical PEALD method, and is not particularly limited. For example, the internal pressure may be in a range of 50 Pa or more, preferably 300 Pa or more, and the upper limit of the internal pressure may be 1300 Pa, and preferably 1000 Pa. In addition, it is preferable to supply a carrier gas while keeping the internal pressure of the chamber 10 constant by discharging the same amount of gas while supplying the carrier gas into the chamber 10.

[Adsorption Step]

Subsequently, a first gas containing at least a source gas component is supplied into the chamber 10, and the source gas component is adsorbed on the metal surface in the chamber 10. Adsorption of the source gas component on the metal surface in the chamber 10 enables a molecular layer of the source gas component to be formed on the metal surface in the chamber 10.

Here, the source gas component contained in the first gas may be a gas used for forming a silicon-containing film by a plasma-enhanced chemical vapor deposition (PECVD) method or a plasma-enhanced atomic layer deposition (PEALD) method. More specifically, a gas containing a chlorosilane compound, which is a compound in which 1 to 4 chlorine atoms are bonded to one silicon atom, can be used as a source gas component. As the chlorosilane compound, one or more selected from the group consisting of dichlorosilane (SiCl₂H₂), trichlorosilane (SiCl₃H), tetrachlorosilane (SiCl₄) and hexachlorodisilane (Si₂Cl₆) can be used. Among them, dichlorosilane (SiCl₂H₂) is preferable from the viewpoint of availability.

When a first gas containing a source gas component is supplied into the chamber 10 in a device having a piping structure shown, for example, in FIG. 2, the source gas can be supplied into the chamber 10 by opening the valve V1 provided between the source gas supply source 21 and the film forming device 1 and closing the valve V2 provided between the source gas supply source 21 and the exhaust port X1.

Here, the first gas may contain a carrier gas in addition to the source gas component. In addition, the carrier gas may be supplied into the chamber 10 separately from the first gas. Using a carrier gas increases the total flow rate of the gas supplied to the chamber 10, and this enables the source gas component to be easily spread over a wider range of the metal surface in the chamber 10.

As the carrier gas, for example, one or more selected from the group consisting of argon (Ar) gas, nitrogen (N₂) gas, and helium (He) gas can be used.

Particularly, in the piping structure shown in FIG. 2, for example, supply of a first gas containing a source gas component and a carrier gas into the chamber 10 can be performed by opening the valves V1 and V5 to combine and mix the source gas supplied from a source gas supply source 21 and the carrier gas supplied from a carrier gas supply source 23 to form the first gas containing the source gas component and the carrier gas.

In addition, by opening at least one of the valves V9, V10, and V11, a carrier gas supplied from carrier gas supply sources 32 and 33 used for forming the second gas or a carrier gas supplied from a carrier gas supply source 41 provided independently of the first gas and the second gas may be supplied into the chamber 10, separately from the first gas.

A supply time period of the source gas component in the adsorption step can be, for example, in the range of 0.05 seconds or more, preferably 0.2 seconds or more, and on the other hand, the upper limit thereof can be 5.0 seconds, and preferably 0.5 seconds. The optimum supply time period of the source gas component can be set based on the type of the source gas component, the internal pressure of the chamber 10, and the like.

[First Purge Step]

After a source gas is supplied, an excessive source gas component not adsorbed on the metal surface in the chamber 10 is discharged out of the chamber 10 (first purge step). This reduces the source gas component remaining in the chamber 10, and even if plasma is generated in the precoat film forming step, which is described below, generation of chlorine due to free chlorine released from the chlorosilane compound can be reduced. This enables a desired precoat film 2 to be formed, while reducing contamination in the chamber 10 due to metal atoms generated by etching of the metal surface in the chamber 10.

Examples of means for discharging an excessive source gas component not adsorbed on the metal surface in the chamber 10 out of the chamber 10 include: a means of supplying a carrier gas into the chamber 10 to purge the source gas component not adsorbed on the metal surface in the chamber 10; a means of evacuating the source gas component by drawing a vacuum in the chamber 10; and a combination thereof. Among them, it is particularly preferable to supply a gas containing a carrier gas into the chamber 10 to purge the source gas component. As described above, since discharging an excessive source gas component not adsorbed on the metal surface in the chamber 10 out of the chamber 10 reduces the amount of free chlorine released from the source gas component when plasma is generated, contamination in the chamber 10 due to etching of the metal surface in the chamber 10 can be reduced.

As the carrier gas used in the first purge step, it is preferable to use one or more selected from the group consisting of argon (Ar) gas, nitrogen (N₂) gas, and helium (He) gas, likewise to the adsorption step.

A carrier gas can be supplied into the chamber 10 by supplying carrier gases supplied from the carrier gas supply sources 22 and 23 used for forming the first gas, the carrier gas supply sources 32 and 33 used for forming the second gas, and the carrier gas supply source 41 provided independently of the first gas and the second gas, into the chamber 10 by opening at least one of the valves V3, V5, V9, V10 and V11 in the piping structure shown in FIG. 2, for example.

Here, it is preferable that the gas flow rate when a valve (in FIG. 2, the valve V3) provided in either one of the carrier gas supply sources 22 and 23 used for forming the first gas is in the open state is the same as the gas flow rate when the valve V1 provided in the source gas supply source 21 is in the open state. Thus, opening one of the valve V1 and the valve V3 allows the source gas and the carrier gas to flow into the chamber 10 at the same flow rate, resulting in easy adjustment of the pressure in the chamber 10.

A gas can be discharged out of the chamber 10 through an exhaust port X3.

[Precoat Film Forming Step]

In the precoat film forming step, a second gas containing a reactant gas is supplied into the chamber 10, and high-frequency power is applied to the gas supply unit 14 in an atmosphere in which the second gas exists in the chamber 10, whereby plasma is generated in the reactant gas component in the second gas (a gas component excited to a plasma), and the second gas whose reactant gas component is activated by plasma generation is brought into contact with a metal surface in the chamber 10. The reactant gas component contained in the second gas is contacted with the source gas component adsorbed on the metal surface to form the precoat film 2 on the metal surface in the chamber 10.

The method for forming the precoat film according to the present embodiment uses a PEALD method and comprises supplying a first gas containing a chlorosilane compound and a second gas containing a reactant gas at different timing to form the precoat film 2. In particular, in the present embodiment, an excessive source gas component not adsorbed on the metal surface is discharged in the first purge step. This enables high-frequency power to be applied in a state where an amount of the chlorosilane compound in the chamber 10 is reduced. This results in reduction in the amount of free chlorine in the chamber 10. Therefore, when forming the precoat film 2, contamination in the chamber 10, which is generated due to chlorine which etches the metal surface, is reduced. Thus, when forming a silicon-containing film on the surface of a substrate W by a PECVD method using a film forming device 1 comprising the chamber 10 in which a precoat film 2 is formed, contamination of the surface of substrate W or the silicon-containing film formed on the surface of the substrate w by metal atoms can be reduced.

Here, application of high-frequency power in the precoat film forming step is performed in an atmosphere in which the second gas exists. More specifically, the application of high-frequency power is performed while the second gas is supplied into the chamber 10 or after the second gas is supplied into the chamber 10. Here, from the viewpoint of increasing the productivity of the precoat film, application of high-frequency power in the precoat film forming step is preferably performed in at least a part of a period during which the second gas is supplied into the chamber 10. Among them, from the viewpoint of leaving as little unreacted reactant gas component as possible in the chamber 10 after the precoat film 2 is formed, it is more preferable to apply high-frequency power so as to include a time point at which the period of supplying the second gas into the chamber 10 ends.

The second gas supplied into the chamber 10 in the precoat film forming step contains at least a reactant gas, and preferably contains a reactant gas and a carrier gas. For example, when a reactant gas and a carrier gas are supplied into the chamber 10 as the second gas, plasma is generated in the reactant gas component comprising one of the reactant gas and the carrier gas or both by applying high-frequency power, and the reactant gas component activated by plasma generation is brought into contact with the source gas component adsorbed on the metal surface in the chamber 10, whereby the reactant gas component reacts with the source gas component, thereby forming the precoat film 2.

As the reactant gas contained in the second gas, a gas capable of reacting with a chlorosilane compound in the presence of plasma generated in the reactant gas component can be used. More specifically, it is preferable to use one or more gases selected from the group consisting of ammonia (NH₃) gas, nitrogen (N₂) gas, a mixed gas of nitrogen (N₂) gas and hydrogen (H₂) gas, hydrazine (N₂H₂) gas, oxygen (O₂) gas, ozone (O₃) gas, nitrous oxide (N₂O) gas, and carbon dioxide (CO₂) gas. As the carrier gas, as described above, it is preferable to use one or more selected from the group consisting of argon (Ar) gas, nitrogen (N₂) gas, and helium (He) gas.

When the second gas containing a reactant gas component is supplied into the chamber 10, using, for example, a device having a piping structure shown in FIG. 2, the reactant gas can be supplied into the chamber 10 by opening the valve V7 provided between a reactant gas supply source 31 and the film forming device 1 and closing the valve V6 provided between the reactant gas supply source 31 and the exhaust port X2.

In particular, in an embodiment including a carrier gas, the valves V7 and V10 are opened, so that a reactant gas supplied from the reactant gas supply source 31 and a carrier gas supplied from the carrier gas supply source 33 are combined and mixed to form a second gas containing a reactant gas component and a carrier gas.

Further, carrier gases supplied from carrier gas supply sources 22 and 23, which are used for forming the first gas independently of the second gas, or a carrier gas supplied from a carrier gas supply source 41 provided independently of the first gas and the second gas may be supplied into the chamber 10, by opening at least one of the valves V3, V5, and V11.

A supply time period of a reactant gas component in the precoat film forming step can be, for example, in the range of 0.05 seconds or more, preferably 0.2 seconds or more, and on the other hand, the upper limit thereof can be 5.0 seconds, preferably 0.5 seconds. The optimum supply time period of a reactant gas component can be set based on the type of the reactant gas component, presence or absence of a carrier gas, internal pressure of the chamber 10, and the like.

Here, it is preferable that the gas flow rate when a valve (valve V9 in FIG. 2) provided in the carrier gas supply source 32 or 33 is opened is the same as the gas flow rate when the valve V7 provided in the reactant gas supply source 31 is opened. Thereby, opening one of the valve V7 and the valve V9 allows the reactant gas and the carrier gas to flow in the chamber 10 at the same flow rate, so that the pressure in the chamber 10 can be easily adjusted.

Power value of high-frequency power when the high-frequency power is applied can be appropriately set within a range in which stable plasma can be generated, and is not particularly limited.

In addition, from the viewpoint of sufficiently reacting a source gas component adsorbed on the metal surface with a reactant gas component, a duration time of application of high-frequency power can be, for example, 0.05 seconds or more, preferably 0.2 seconds or more. On the other hand, the upper limit of the time for which high-frequency power is applied can be, for example, 600 seconds or less, preferably 20 seconds or less, from the viewpoint of increasing productivity.

A reactant gas component is activated by plasma generation from the reactant gas component contained in the second gas by application of high-frequency power in an atmosphere in which the second gas exists, and, for example, radicals of the reactant or carrier gas, atoms of the reactant or carrier gas, and plasma of the reactant or carrier gas are generated. Then, the reactant gas contained in the second gas reacts with a source gas component adsorbed on the metal surface in the chamber 10 by the action of the reactant gas component activated by plasma generation, whereby a single layer of the precoat film 2 can be formed at least on the metal surface in the chamber 10.

The precoat film 2 is formed on the metal surface in the chamber 10 by the precoat film forming step. More specifically, it is preferable that the precoat film 2 is formed on the inner wall surface of the chamber 10, and surfaces of the mounting table 12, the supporting member 13 thereof, and the gas supply unit 14. The precoat film 2 may be formed on a non-metal surface in the chamber 10, and may be formed on a surface of the support member 16 made of an insulating material such as quartz.

[Second Purge Step]

After the single layer of the precoat film 2 is formed by the precoat film forming step, it is preferable to perform a second purge step comprising discharging a reaction by-product and an unreacted reactant gas out of the chamber 10. Here, examples of means for discharging the reaction by-product and the unreacted reactant gas out of the chamber include a means of purging the reaction by-product and the unreacted reactant gas by supplying a carrier gas into the chamber 10; a means of evacuating the reaction by-product and the unreacted reactant gas by drawing a vacuum in the chamber 10; and a combination thereof.

For example, in the piping structure shown in FIG. 2, the carrier gas can be supplied into the chamber 10 by opening at least one of the valves V3, V5, V9, V10, and V11 in the same manner as in the first purge step described above, thereby a carrier gas from the carrier gas supply source 22 or 23 used for forming the first gas, a carrier gas from the carrier gas supply source 32 or 33 used for forming the second gas, or a carrier gas from the carrier gas supply source 41 provided independently of the first gas and the second gas can be supplied into the chamber 10.

[Formation of Precoat Film with a Desired Thickness]

After the reaction by-product or unreacted reactant gas is discharged out of the chamber 10 by the second purge step, the thickness of the precoat film 2 can be adjusted to form a precoat film 2 with a desired thickness on the metal surface in the chamber 10 by repeating a plurality of cycles, each including an adsorption step comprising supplying a first gas into the chamber so that the source gas component adsorbs on a metal surface in the chamber 10, a first purge step comprising discharging an excessive source gas component not adsorbed on the metal surface out of the chamber 10, a precoat film forming step comprising applying high-frequency power in an atmosphere in which the second gas containing the reactant gas exists in the chamber 10 to generate plasma in the reactant gas component, so that the reactant gas component reacts with the source gas component to form the precoat film, and a second purge step comprising discharging a by-product out of the chamber. Here, the desired thickness of the precoat film 2 is not particularly limited, but may be, for example, in the range of 0.01 μm or more and 1 μm or less.

<<Method for Manufacturing Silicon-Containing Film>>

The method for forming a silicon-containing film according to the present embodiment comprises: forming a precoat film on a metal surface in a chamber, using a PEALD method, and then forming a silicon-containing film on a substrate in the chamber using a PECVD method. The PEALD method comprises: an adsorption step comprising supplying a first gas comprising a chlorosilane compound as a source gas component into the chamber, so that the source gas adsorbs on an inner wall surface of the chamber and a surface of a metal part disposed in the chamber; a first purge step comprising discharging an excessive source gas component not adsorbed on the metal surface in the chamber, out of the chamber; and a precoat film forming step comprising supplying a second gas comprising a reactant gas into the chamber and applying high-frequency power in an atmosphere in which the second gas exists in the chamber, to generate plasma in the reactant gas component in the second gas, so that the reactant gas reacts with the source gas component adsorbed on the metal surface in the chamber to form the precoat film on the metal surface. The PECVD method comprises: disposing a substrate in the chamber; supplying at least the source gas component and the reactant gas component into the chamber; and applying high-frequency power in an atmosphere in which both the source gas component and the reactant gas component exist in the chamber, to generate plasma to form the silicon-containing film on the surface of the substrate.

In the manufacturing method of silicon-containing film according to the present embodiment, after performing the formation of the precoat film by the PEALD method described above, a substrate is disposed in the chamber in which the precoat film is formed, at least a source gas component and a reactant gas component are supplied into the chamber, and plasma is generated in an atmosphere in which both the source gas component and the reactant gas exist in the chamber by using the PECVD method to form the silicon-containing film on the surface of the substrate. As a result, contamination in the chamber due to metal atoms when forming the precoat film is reduced, and the precoat film protects the metal surface in the chamber from being etched by chlorine when the silicon-containing film forming step is performed. Therefore, in the formation of a silicon-containing film on a substrate using a PECVD method, contamination by metal atoms can be reduced.

<Precoat Film Forming Step>

Among them, the precoat film forming step comprises: an adsorption step comprising supplying a first gas containing a chlorosilane compound as a source gas component into the chamber 10 made of metal, so that the source gas component adsorbs on the metal surface in the chamber 10 including an inner wall surface of the chamber 10 and a surface of a metal part disposed in the chamber 10 (the mounting table 12, the supporting member 13 thereof, the gas supply unit 14, and the like); a first purge step comprising discharging an excessive source gas component not adsorbed on the metal surface in the chamber 10 out of the chamber 10; and a step of forming the precoat film 2 on the metal surface using a PEALD method by applying high-frequency power in an atmosphere in which the second gas exists in the chamber 10 to generate plasma in the reactant gas component in the second gas, so that the reactant gas reacts with the source gas component adsorbed on the metal surface in the chamber 10. Since this precoat film forming step is performed by the same method as the precoat film forming method described above, the detailed description thereof is omitted.

<Silicon-Containing Film Forming Step>

The silicon-containing film forming step is a step in which a substrate W is disposed in the chamber 10 in which the precoat film 2 is formed, at least a source gas component and a reactant gas component are supplied into the chamber 10, and plasma is generated in an atmosphere in which both the source gas component and the reactant gas exist in the chamber to form the silicon-containing film on the surface of the substrate W by using a PECVD method.

The silicon-containing film formed in the present embodiment has the same composition system as that of the precoat film 2 described above, and examples thereof include an SiN film or a SiO₂ film. These silicon-containing films are formed on the surface of the substrate W, the surface of which is less contaminated by elemental metal contained in the metal surface in the chamber 10, and are less likely to be contaminated by elemental metal while and after the silicon-containing film is formed. For this reason, these silicon-containing films have desired characteristics and can be suitably used as an insulating film or the like in the process of manufacturing semiconductors.

[Substrate and Preparation Thereof]

The substrate W is carried into the chamber 10 in which the precoat film 2 is formed, and is mounted and held on the mounting table 12. Here, as the substrate W, a silicon substrate, a germanium substrate, or the like can be used, but the substrate W is not limited thereto. The substrate W can be carried into the chamber 10 in a vacuum-state by using a load lock chamber (not shown) or the like.

The substrate W mounted on the mounting table 12 is heated using a heater. Here, the heating temperature of the substrate W can be set, for example, to a range of 300 to 500° C., and is preferably maintained at a constant temperature until a silicon-containing film is formed.

At the same time, the internal pressure in the chamber 10 is depressurized and the carrier gas is supplied. Here, the type of the carrier gas and the range of the internal pressure of the chamber 10 can be set within the same range as in the precoat film forming step described above.

[Formation of Silicon-Containing Film]

Subsequently, at least a source gas component such as a chlorosilane compound and a reactant gas component are supplied into the chamber 10, plasma is generated in an atmosphere in which both the source gas component and the reactant gas exist, and a silicon-containing film is formed on the surface of a substrate W by a PECVD method. At this time, at least one of the source gas component and the reactant gas component is activated by plasma generation, so that the reaction between the source gas and the reactant gas is accelerated, and thus a silicon-containing film can be formed on the surface of a substrate W. At this time, the source gas component is activated or reacts with the reactant gas component and chlorine or a chlorine compound is generated. However, since the metal surface in the chamber 10 is protected by the precoat film 2, the substrate W or the silicon-containing film is less likely to be contaminated due to etching of the metal surface.

Here, as one of the source gas component and the reactant gas component or both, it is preferable to use the same one as that used in the precoat film formation described above. As a result, a precoat film can be formed and a silicon-containing film can be formed without using a special facility for forming a precoat film, and thus it is possible to prevent a substrate W or the like from being contaminated by elemental metal, using a simpler method while avoiding complication of device configuration.

When supplying a source gas component and a reactant gas component into the chamber 10, for example, in a device having a piping structure shown in FIG. 2, the source gas and the reactant gas can be supplied into the chamber 10 by opening a valve V1 provided between the source gas supply source 21 and the film forming device 1 and a valve V7 provided between the reactant gas supply source 31 and the film forming device 1.

A gas supplied into the chamber 10 may include a carrier gas in addition to a source gas and a reactant gas. In addition, a carrier gas may be supplied into the chamber 10 separately from the source gas and the reactant gas. Here, it is also preferable to use the same carrier gas as that used in the method for forming the precoat film, from the viewpoint of no special equipment being required for forming the precoat film. In particular, when a reactant gas and a carrier gas are supplied into the chamber 10, plasma is generated in the reactant gas component comprising one of the reactant gas and the carrier gas or both by applying high-frequency power, and the reactant gas component activated by plasma generation is brought into contact with the source gas component, so that the reactant gas reacts with the source gas component, and thereby a silicon-containing film can be formed.

In particular, when a carrier gas is supplied into the chamber 10, a source gas component and a reactant gas component may be supplied into the chamber 10 by opening one of the valves V3 and V9 or both in addition to the valves V1 and V7, so that a source gas supplied from the source gas supply source 21 and a carrier gas supplied from the carrier gas supply source 23 are combined, or a reactant gas supplied from the reactant gas supply source 31 and a carrier gas supplied from the carrier gas supply source 33 are combined. Thereby, a first gas containing a source gas and a carrier gas and a second gas containing a reactant gas and a carrier gas are formed, and these can be supplied into the chamber 10.

In addition, by opening the valve V11, a carrier gas supplied from the carrier gas supply source 41 provided independently of the source gas and the reactant gas may be supplied into the chamber 10.

When forming a silicon-containing film, high-frequency power is applied in an atmosphere in which both the source gas component and the reactant gas component exist in the chamber 10. More specifically, it is preferable that application of high-frequency power in forming a silicon-containing film is performed during at least a part of the period during which a source gas component and a reactant gas component are supplied into the chamber 10. Among them, from the viewpoint of leaving as little unreacted source gas component or a reactant gas component as possible in the chamber 10, it is more preferable to apply high-frequency power so as to include a time point at which the period of supplying at least one of the source gas component and the reactant gas component into the chamber 10 ends.

A power value of the high-frequency power when the high-frequency power is applied can be appropriately set within a range in which stable plasma can be generated, and is not particularly limited.

When forming a silicon-containing film, a time period for supplying a source gas component and a reactant gas component and a time period for applying high-frequency power can also be set depending upon the thickness of a desired silicon-containing film, and are not particularly limited.

Such plasma generated in a source gas component and a reactant gas component activates one of the source gas component and the reactant gas component or both, and this generates, for example, radicals of the source gas, the reactant gas and the carrier gas; constituent atoms of the source gas, the reactant gas and the carrier gas, and plasma of the source gas, the reactant gas and the carrier gas. Action of components activated by plasma generation results in reaction of the reactant gas and the source gas, whereby a silicon-containing film having a desired thickness can be formed on the surface of the substrate W.

Example

The Example of the present invention is described below, but the present invention is not limited to this Example, as far as not exceeding the technical concept of the present invention.

Example

The Examples describe an embodiment in which a precoat film is formed using a plasma-enhanced atomic layer deposition (PEALD) method, and then a silicon-containing film is formed by a plasma-enhanced chemical vapor deposition (PECVD) method.

[Precoat Film Forming Step]

As shown in FIG. 1, a film forming device 1 which was used comprises a chamber 10 comprising a mounting table 12 with a diameter of 335 mm, which can mount a substrate Won a top surface thereof and function as a lower electrode, and a gas supply unit 14 with a diameter of 347 mm, which functions as an upper electrode. Here, as the mounting table 12, a mounting table made of aluminum nitride ceramics was used, and as the gas supply unit 14, a gas supply unit made of an aluminum (Al) alloy was used. Further, for some of the metal parts disposed in the chamber 10, parts made of an alloy containing copper (Cu) were used. Further, the size of a gap D between the mounting table 12 functioning as a lower electrode and the gas supply unit 14 functioning as an upper electrode was set to 13 mm.

Using the chamber 10 whose inner wall surface was made of an aluminum (Al) alloy, a substrate W was heated to a temperature of 450° C. using a heater built in the mounting table 12 without mounting the substrate W on the mounting table 12. Along with this, the internal pressure was reduced to 533 Pa while supplying a carrier gas comprising argon (Ar) gas at a flow rate of 3.50 slm and nitrogen (N₂) gas at a flow rate of 0.50 slm.

As the adsorption step, a first gas comprising a source gas containing dichlorosilane (SiCl₂H₂) at a flow rate of 1.00 slm, argon (Ar) gas at a flow rate of 2.50 slm, and nitrogen (N₂) gas at a flow rate of 0.50 slm was supplied for a supply time period of 0.5 seconds into the chamber 10 under a reduced pressure, to form a molecular layer of the source gas on the metal surface in the chamber 10.

Thereafter, the first purge step was performed by stopping supply of the source gas and increasing the flow rate of argon (Ar) gas instead, so that a carrier gas comprising argon (Ar) gas at a flow rate of 3.50 slm and nitrogen (N₂) gas at a flow rate of 0.50 slm was supplied into the chamber 10 for 0.2 seconds, and the surplus source gas component not adsorbed on the metal surface in the chamber 10 was discharged out of the chamber 10.

Then, the precoat film forming step was performed in the chamber 10 by combining and mixing a reactant gas comprising ammonia (NH₃) at a flow rate of 3.00 slm, argon (Ar) gas at a flow rate of 0.50 slm, nitrogen (N₂) gas at a flow rate of 0.50 slm; supplying a second gas comprising these in a supply time period of 0.2 seconds, and then while supplying the second gas into the chamber 10, applying high-frequency power of the power value of 108 W for 1.0 second to the gas supply unit 14, to generate plasma in the reactant gas component in the second gas so that this reacts with the source gas component adsorbed on the metal surface in the chamber 10, to form a molecular layer comprising silicon nitride (SiN).

Thereafter, the second purge step was performed by stopping supply of the reactant gas and increasing the flow rate of argon (Ar) gas instead, so that a carrier gas comprising argon (Ar) gas at a flow rate of 3.50 slm and nitrogen (N₂) gas at a flow rate of 0.50 slm was supplied into the chamber 10 for 0.1 seconds, and reaction by-products and an unreacted reactant gas were discharged out of the chamber 10.

Thereafter, under the same conditions, a cycle comprising an adsorption step comprising supplying a first gas into the chamber so that a source gas component adsorbs on a metal surface in the chamber 10, a first purge step comprising discharging an excessive source gas component not adsorbed on the metal surface out of the chamber 10, a precoat film forming step comprising applying high-frequency power in an atmosphere in which a second gas containing a reactant gas exists in the chamber 10 to generate plasma in the reactant gas component, so that the reactant gas component reacts with the source gas component to form a precoat film, and a second purge step comprising discharging a by-product out of the chamber was performed repeatedly by 10,000 cycles, to form a precoat film comprising silicon nitride (SiN) having a thickness of 600 nm. Thereafter, in order to prevent the source gas or the reactant gas, which are process gases, from flowing into a lower portion of the chamber 10, which is outside the desired reaction area, nitrogen (N₂) gas having a flow rate of 2.0 slm was flowed into the chamber 10 as a sealing gas.

[Silicon-Containing Film Forming Step]

(Preparation for Silicon-Containing Film Formation)

Using the chamber 10 in which a precoat film is formed on a metal surface, a silicon substrate having a diameter of 300 mm was mounted as the substrate W, and heated to a temperature of 500° C. using a heater built in the mounting table 12. Along with this, the internal pressure was reduced to 200 Pa while supplying a carrier gas comprising argon (Ar) gas having a flow rate of 2.75 slm and nitrogen (N₂) gas having a flow rate of 1.50 slm.

(Forming Silicon-Containing Film)

A source gas comprising dichlorosilane (SiCl₂H₂) at a flow rate of 0.10 slm and a reactant gas comprising ammonia (NH₃) at a flow rate of 0.50 slm were supplied into the chamber 10 under reduced pressure, and while argon (Ar) gas at a flow rate of 2.75 slm and nitrogen (N₂) gas at a flow rate of 1.50 slm were supplied as the carrier gas, high-frequency power having a power of 163 W was applied to the gas supply unit 14 for 12.8 seconds to generate plasma, to form a silicon-containing film with a thickness of 8 nm comprising silicon nitride (SiN) on the surface of substrate W. With respect to the silicon-containing film formed on the surface of the substrate W and the back surface of the substrate W on which a silicon-containing film was not formed and on which circulation of metal atoms caused contamination, abundances (atoms/cm²) of copper (Cu) atoms, zinc (Zn) atoms, chromium (Cr) atoms, aluminum (Al) atoms, magnesium (Mg) atoms, yttrium (Y) atoms, calcium (Ca) atoms, and potassium (K) atoms were evaluated using an inductively coupled plasma mass spectrometer (ICP-MS).

FIGS. 3 and 4 are graphs showing variations in the flow rate of a chlorosilane compound (dichlorosilane) as the source gas, the flow rate of ammonia as the reactant gas, power values (on/off patterns) of high-frequency power (RF-plasma), and a combined flow rate of argon gas and nitrogen gas as the carrier gas, in the precoat film forming step and the silicon-containing film forming step, respectively. Incidentally, vertical axes shown in FIGS. 3 and 4 do not represent absolute values, but conceptionally show an increase or decrease in the flow rate of the gas and on/off patterns of the power value.

As a result, abundances of copper (Cu) atoms, zinc (Zn) atoms, chromium (Cr) atoms, aluminum (Al) atoms, magnesium (Mg) atoms, yttrium (Y) atoms, calcium (Ca) atoms and potassium (K) atoms in the silicon-containing film formed on the surface of the substrate W and abundances of these metal atoms on the back surface of the substrate W were as shown in Table 1.

Comparative Example

a. In the Comparative Example, a precoat film was formed using a plasma-enhanced chemical vapor deposition (PECVD) method, and then a silicon-containing film was formed using the plasma-enhanced chemical vapor deposition (PECVD) method.

[Precoat Film Formation]

As shown in FIG. 1, a film forming device 1 was used which comprises a chamber 10 comprising a mounting table 12 with a diameter of 335 mm, on a top surface of which a substrate W can be mounted and which functions as a lower electrode, and a gas supply unit 14 with a diameter of 347 mm, which functions as an upper electrode. Here, as the mounting table 12, a mounting table made of aluminum nitride ceramics was used, and as the gas supply unit 14, a gas supply unit made of aluminum (Al) alloy was used. Further, for some of metal parts disposed in the chamber 10, parts made of an alloy containing copper (Cu) were used. Further, the size of the gap D between the mounting table 12 functioning as a lower electrode and the gas supply unit 14 functioning as an upper electrode was set to 13 mm.

Using the chamber 10 whose inner wall surface was made of an aluminum (Al) alloy, the inside of the chamber 10 was heated to a temperature of 500° C. using a heater built in the mounting table 12, without mounting a substrate W on the mounting table 12 in the chamber 10. Along with this, the internal pressure was reduced to 200 Pa while supplying a carrier gas comprising argon (Ar) gas at a flow rate of 2.75 slm and nitrogen (N₂) gas at a flow rate of 1.50 slm.

While supplying a source gas containing dichlorosilane (SiCl₂H₂) at a flow rate of 0.10 slm and a reactant gas comprising ammonia (NH₃) at a flow rate of 0.50 slm, as well as argon (Ar) gas at a flow rate of 2.75 sml and nitrogen (N₂) gas at a flow rate of 1.50 slm as the carrier gas into the chamber 10 under a reduced pressure, high-frequency power of the power value of 163 W was applied to the gas supply unit 14 for 960 seconds, to generate plasma, to form a precoat film with a thickness of 600 nm comprising silicon nitride (SiN) on the metal surface in the chamber 10.

Thereafter, using the chamber 10 in which a precoat film is formed on the metal surface, under the same conditions as in the Example, a silicon-containing film with a thickness of 8 nm comprising silicon nitride (SiN) was formed on the substrate W. With respect to the silicon-containing film formed on the surface of the substrate W and the back surface of the substrate W on which a silicon-containing film was not formed and on which circulation of metal atoms caused contamination, abundances (atoms/cm²) of copper (Cu) atoms, zinc (Zn) atoms, chromium (Cr) atoms, aluminum (Al) atoms, magnesium (Mg) atoms, yttrium (Y) atoms, calcium (Ca) atoms, and potassium (K) atoms were evaluated likewise to the Example.

As a result, abundances of copper (Cu) atoms, zinc (Zn) atoms, chromium (Cr) atoms, aluminum (Al) atoms, magnesium (Mg) atoms, yttrium (Y) atoms, calcium (Ca) atoms and potassium (K) atoms in the silicon-containing film formed on the surface of the substrate W and abundances of these metal atoms on the back surface of the substrate W were as shown in Table 1.

TABLE 1 Metal atom Cu Zn Cr Al Mg Y Ca K Example Abundances of metal atoms 0.95 0.28 0.09 1.02 <0.01 <0.01 <0.01 0.01 on silicon-containing film formed on the surface of substrate W [atoms/cm²] Abundances of metal atoms 2.10 0.43 0.02 4.53 0.02 0.01 <0.01 0.04 on the back surface of the substrate w [atoms/cm²] Comparative Abundances of metal atoms 12.86 0.19 0.11 12.68 0.03 <0.01 <0.01 0.15 Example on silicon-containing film formed on the surface of substrate W [atoms/cm²] Abundances of metal atoms 25.83 0.43 0.09 21.73 0.03 <0.01 0.11 0.15 on the back surface of the substrate w [atoms/cm²]

SUMMARY

The above results indicate that in the Example in which a precoat film was formed using a plasma-enhanced atomic layer deposition (PEALD) method, and then a silicon-containing film was formed using a plasma-enhanced chemical vapor deposition (PECVD) method, abundances of metal atoms in the silicon-containing film formed on the surface of a substrate W, in particular, abundances of aluminum (Al) atoms and copper (Cu) atoms were both reduced compared to the Comparative Example, and abundances of metal atoms, in particular, aluminum (Al) atoms and copper (Cu) atoms which circulated onto the back surface of the substrate W before the silicon-containing film was formed, were both reduced. Therefore, it has been found that forming a precoat film using the plasma-enhanced atomic layer deposition (PEALD) method can reduce contamination of a substrate surface or a silicon-containing film formed on the substrate surface by these metal atoms.

EXPLANATION OF REFERENCE NUMERALS

-   -   1 Film forming device     -   2 Precoat layer     -   10 Chamber     -   11 Insertion hole     -   12 Mounting table     -   13, 16 Supporting member     -   14 Gas supply unit     -   15 Gas supply hole     -   21 Source gas supply source     -   31 Reactant gas supply source     -   22, 23, 32, 33, 41 Carrier gas supply source     -   D Gap between the mounting table and the gas supply unit     -   W Substrate     -   V1 to V11 Valves     -   X1 to X3 Exhaust port 

What is claimed is:
 1. A method for forming a precoat film on a metal surface in a metal chamber before forming a silicon-containing film having an identical composition system with that of the precoat film on a substrate in the chamber using a PECVD method, with the metal surface including an inner wall surface of the chamber and a metal surface of a metal part disposed in the chamber, with the PECVD method comprising at least supplying a first gas comprising a chlorosilane compound as a source gas component and a second gas comprising a reactant gas into the chamber comprising the substrate disposed, and applying high-frequency power in an atmosphere in which both the source gas and the reactant gas exist in the chamber, to generate plasma, so that the silicon-containing film is formed on the substrate, wherein the precoat film is formed using a PEALD method in which a first gas and a second gas are supplied into the chamber by shifting timing of supply, wherein the method for forming a precoat film comprises an adsorption step comprising supplying the first gas into the chamber, so that the source gas component adsorbs on the metal surface, a first purge step comprising discharging an excessive source gas component not adsorbed on the metal surface in the chamber, out of the chamber, and a precoat film forming step comprising supplying the second gas into the chamber and applying high-frequency power in an atmosphere in which the second gas exists in the chamber, to generate plasma in the reactant gas component in the second gas, so that the reactant gas component reacts with the source gas component adsorbed on the metal surface in the chamber to form the precoat film on the metal surface.
 2. The method for forming a precoat film according to claim 1, wherein the chlorosilane compound comprises one or more selected from the group consisting of dichlorosilane (SiCl₂H₂), trichlorosilane (SiCl₃H), tetrachlorosilane (SiCl₄) and hexachlorodisilane (Si₂Cl₆).
 3. The method of forming a precoat film according to claim 1, wherein the chlorosilane compound comprises dichlorosilane (SiCl₂H₂).
 4. The method for forming a precoat film according to claim 1, wherein the reactant gas comprises one or more selected from the group consisting of ammonia (NH₃) gas, nitrogen (N₂) gas, a mixed gas of nitrogen (N₂) gas and hydrogen (H₂) gas, hydrazine (N₂H₂) gas, oxygen (O₂) gas, ozone (O₃) gas, nitrous oxide (N₂O) gas, and carbon dioxide (CO₂) gas.
 5. The method for forming a precoat film according to claim 1, wherein the precoat film comprises an SiO₂ film or an SiN film.
 6. The method for forming a precoat film according to claim 1, wherein application of high-frequency power in the precoat film forming step is performed in at least a part of a period during which the second gas is supplied into the chamber.
 7. The method for forming a precoat film according to claim 1, wherein the first gas comprises a source gas and a carrier gas, and the second gas comprises a reactant gas and a carrier gas.
 8. The method for forming a precoat film according to claim 1, wherein the method further comprises a second purge step comprising discharging a reaction by-product and an unreacted reactant gas out of the chamber after the precoat film forming step, and wherein a thickness of the precoat film is adjusted by repeating an atomic layer deposition (ALD) cycle in which the adsorption step, the first purge step, the precoat film forming step, and the second purge step are sequentially performed a plurality of times.
 9. A method for producing a silicon-containing film, the method comprising: forming a precoat film on a metal surface in a metal chamber, using a PEALD method, and then forming a silicon-containing film on a substrate in the chamber using a PECVD method, wherein the PEALD method comprises: an adsorption step comprising supplying a first gas comprising a chlorosilane compound as a source gas component into the chamber, so that the source gas adsorbs on the metal surface in the chamber, with the metal surface including an inner wall surface of the chamber and a surface of a metal part disposed in the chamber, a first purge step comprising discharging an excessive source gas component not adsorbed on the metal surface in the chamber, out of the chamber, and a precoat film forming step comprising supplying a second gas comprising a reactant gas into the chamber, and applying high-frequency power in an atmosphere in which the second gas exists in the chamber, to generate plasma in the reactant gas component in the second gas, so that the reactant gas reacts with the source gas component adsorbed on the metal surface in the chamber to form the precoat film on the metal surface; and wherein the PECVD method comprises disposing a substrate in the chamber, supplying at least a source gas component and a reactant gas component into the chamber, and applying high-frequency power in an atmosphere in which both the source gas component and the reactant gas component exist in the chamber, to generate plasma to form the silicon-containing film on the surface of the substrate. 